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About Initialization Parameters

Managing an Oracle instance includes configuring parameters that affect thc basie operation of the Oracle instance. Thesc parameters arc called initialization parameters. The Oracle instance reads initialization parameters from a file at startup.

During installation, when you select a preconfigured database workload available in DBCA, the initialization parameters are optimized for typical usc in the environment that you specified. As the number of database users inereases and the workload inereases. you might have to alter some initialization parameters. You can make these changes using the Initialization Parameter page in EM Exprcss, or by using an advisor provided by Oracle Database, such as the Memory Advisor. See "Optimizing Memory Usage with the Memory Advisors" on page 10-31 for morę information.

After bcing read from a file. initialization parameters are retained in memory, where the values for many of them can be changed dynamically. There are two types of parameter files. The type of file used to start the instance determines if dynamie initialization parameter changes persist across database shutdown and startup. The parameter file types are:

■Server parameter file

The server parameter file, commonly known as the SPFILE, is the preferred form of initialization parameter file, and is a binary file that can be written to and read by the database. It must not be edited manuałly. It is stored on the host Computer on which Oracle Database is running. Changes are madę when you use EM Exprcss or SQL*Plus to modify one or morę initialization parameters, or when Oracle Database itself makes changes for self-tuning purposes. Any changes to it persist across database shutdown and startup operations.